Statistics of single-electron signals in electron-multiplying charge-coupled devices

Electron-multiplying charge coupled devices promise to revolutionize ultrasensitive optical imaging. The authors present a simple methodology allowing reliable measurement of camera characteristics and statistics of single-electron events, compare the measurements to a simple theoretical model, and report camera performance in a truly photon-counting regime that eliminates the excess noise related to fluctuations of the multiplication gain.

I. Introduction

AN ELECTRON-MULTIPLYING charge coupled device (EMCCD) is an advanced imaging device that contains an additional multiplication register creating a multielectron charge package for every primary electron via an impact-ionization cascade [1]. As a result, the relative contribution of the readout noise is reduced dramatically [2], [3]. Such cameras are most valuable for ultrasensitive imaging (including single-molecule microscopy and detection). Ultimately, sensitivity is hindered by various sources of noise, and analysis of noise in an EMCCD at the single-photon detection level is the major subject of this paper.